Upgrade to Payload CMS v3

[m453h]

Payload CMS v3 has been available for a while now.

We need to upgrade each individual app that uses Payload in this repo to the latest version of Payload to take advantage of the latest features and improvements. However from the release notes of v3 it is indicated that:

This is a major release that includes a re-architecture of Payload from an Express + React Router SPA to the Next.js App Router + RSCs. In addition to this architectural change, we've also shipped a ton of large features, miscellaneous fixes, and DX improvements.

Will this integrate well with our apps since we are using pages router ?

Additionally here are some of the things that were discussed in the past that could be revisited once the upgrade is done:

• Migrating from the legacy Slate Editor to Rich Text editor.
• Allow users to create tables within the CMS (perhaps integrating with lexical table
• Using one CMS to manage content of all apps that use Payload CMS.

[kilemensi]

Yeah, we definitely need to break this down @m453h.

My current thinking/understanding (which could be totally wrong) is:

1. app router and page router can co-exist in the same app.
2. you should avoid clashes of routes but if there are any, I believe app router will be matched first.

If this is correct, our first (sub)task should then just be to upgrade Payload and use app router only for Payload i.e. leaving the rest of our code base unchanged.

[kilemensi]

I'd say lets create sub-issues here @m453h ... may be:

1. Upgrade Payload to v3 on codeforafrica app alone.
2. Upgrade Payload to v3 for the rest of the apps.

Issue 1 should help surface any risks with the upgrade & it will be easier for the team to review quickly.

PS: Epics (Issues with type Epic) shouldn't really be included in TODO, etc. They're used for organising related work but should just remain in Backlog.